William mack ay



(No Model.)

W. MAGKAY. BED FOR METALLIC PRINTING PLATES.

Patented July 21, 1891.

INVENTOH:

Br A77'0l-7NEYS WITNESSES:

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UNITED STATES PATENT OFFICE.

\VILLIAM MAGKAY, OF NEW YORK, N. Y., ASSIGNOR TO JULIUS BIEN & 00.,

OF SAME PLACE.

BED FOR METALLIC PRINTING-PLATES.

SPECIFICATION formingpart of Letters Patent No. 456,502, dated July 21,1891.

Application filed April 30, 1890- Serial No. 350,037. (No model.)

To all whom it may concern.-

Be it known that I, \VILLIAM MACKAY, of the city, county, and State ofNew York, have invented a new and Improved Bed for Me- 5 tallicPrintingPlates, of which the following is a full, clear, and exactdescription.

The invention relates to printing from metallic plates, and its objectis to provide a new and improved bed for conveniently supportingmetallic plates during the process of printing, and which is simple anddurable in construction, securely holds the platein position, andpermits of adjusting the plate so that the latter presents an absolutelytrue surface to insure accurate printing.

The invention consists of certain parts and details and combinations ofthe same, as will be hereinafter fully described, and then pointed outin the claims.

Reference is to be had to theaccompanying drawings, forming a part ofthis specification, in which similar letters of reference indicatecorresponding parts in all the figures.

Figure l is a broken side elevation of the improvement. Fig. 2 is areduced view of one end of the improvement. Fig. 3 is a like view of theother end. Fig. 4 is a perspective view of one of the lever-clamps, andFig. 5 is a side elevation of a modified form of the improvement.

The improved bed A for metallic printingplates is provided with the bedB proper, on the top of which is placed the metallic printing-plate O,containingthe matterto be printed onto the paper or other material inthe usual manner. One end of the plate 0 passes over the rounded end Dof the bed proper B, and is secured at its end between the end of thebed B and a clamping-plate E, fastened onto the end of the bed B byset-screws F, as is plainly shown in Figs. 1 and 3. The other end of theplate C passes over the downwardly-beveled end D of the bed B, and isadapted to be clamped between the jaws H I of the lever-clamps G. Thejaws I of the clamps G have their front edges beveled so as to be belowthe top surface of the plate C, and. are held in place on the jaws II bythe set-screws J. The jaws I are prevented from sliding on the jaws H byrecesses 1 fitting onto shoulders K, formed on the rear ends of the jawsH.

Each jaw II extends downward on the end of the bed proper B, and isprovided on its inner side with a rounded lug L, adapted to engage atransversely-extending groove N, formed in the end of the bed B. Thislug L forms the fulcrum for each clamp G, so that the latter can swingoutward at its up er end in order to stretch the plate C firmly on thetop of the bed proper B.

In the lower end of each jaw H are formed slots 0, through which passbolts P, secured in the end of the bed proper B. A washer Q is placedtransversely across thelower end of each jaw H, and nuts R, screwing onthe outer ends of the bolts P, screw up against the said washers Q, soas to adjust each clamp G, as hereinafter more fully described.

The operation is as follows: The metallic plate 0 is first clamped withone end between the plate E and the end of the bed B by adj usting theset-screws F. The plate 0 is then passed over the rounded part D of thebed proper B, over the top surface of the latter, and then the free endof the said plate 0 is clamped between the jaws I and II of the severalclamps G, which latter are placed with their lugs L in the transversegroove N, and with the bolts P passing through the slots 0, aspreviously described. The operator then screws up the nuts B, so as tomove the lower part of each fixed jaw H inward, while the upper partwith the plate 0 swings outward, the said clamps turning on the lugs Las a fulcrum. By thus swinging the upper ends of the clamps G outwardthe plate 0 is stretched over the top surface of the bed proper B, andby adjusting the nuts of the several clamps G according to the conditionof the plate C the latter can be conveniently stretched on the topsurface of the bed proper B, so that its printingsurface is absolutelytrue. The bed B with the plate 0 adjusted as described is used in theprinting-press in the usual manner, so that an absolutely correctimpression is obtained from the plate 0. For short plates 0 theclamping-plate E is dispensed with, and similar sets of clamps G areused on each end of the bed proper B, as is plainly shown in 100 Fig. 5.For this purpose this end of the bed 13 is provided with an offset Dengaged at its under side by the lugs L of the clamps G, so as to form afulcrum for the latter. In this case the plate G is first inserted intothe jaws H and I of one set of clamps G, at one end of the bed B, andthen secured in the other set of clamps G at the other end of the bed,after which one or both sets of clamps are adjusted-as previouslydescribed, so that the plate is evenly stretched on the top surface ofthe bed-plate 13.

Having thus fully described my invention, I claim as new and desire tosecure by Letters Patent 1. The combination, with a bed for supportingmetallic printing-plates,of a clamp fulcrumed on the'end of the bed andprovided with an opening in its lower end, and a screw-bolt secured tothe end of the bed, projecting through the opening of the clamp, andprovided with a nuton its end, substantially as herein shown anddescribed.

2. In a bed for metallic printing-plates, the combination, with the bedproper provided with a transversely-extending recess, of a clamp-leveradapted to engage one end of the printing-plate, a rounded lug formed onthe said clamp-lever and engaging the said transverse recess, and boltsand nuts for adjusting the said clamp-lever on the end of the said bed,substantially as shown and described.

3. In a bed for metallic printing-plates, a clamp consisting of a jawprovided with a lug on its inner side at about the center and with slotsin its lower end and a second jaw detachably secured to the upper end ofthe first-named jaw, substantially as described.

4. In a bed for metallic printingplates, a clamp consisting of a jawprovided with a shoulder on its upper face, a rounded projection on itsinner face, and slots in its lower end, and a second jaw secured on theupper end of the first-named jaw and having its front edge beveled andprovided with a recess in its under face engaging the shoulder of theotherj aw, substantially as herein shown and described.

. WILLIAM l\'lACKAY. \Vitnesses:

P. J. FORD, JULiUs BIEN, Jr,

